In particular with respect to the fact that modern manufacturing plants are increasingly equipped with automatic tool change systems, there has been a growing need for modular tool systems.
In systems of this kind for instance a precision-manufactured chuck shaft or shank of a tool receiver to which a system of different tools can be coupled is used. Great demands with respect to the flux of force, concentric running and positioning accuracy are made to a coupling system adjusted thereto
Already various attempts have been made to provide a universally applicable coupling system which meets the above-mentioned criteria. So, for instance, it has been suggested to employ, in the area of the coupling, a self-centering serration which should bring about the positive connection of the parts in conjunction with a collet chuck. This kind of coupling, however, has been restricted to the interface, i.e. the intermediate portion between tool and the basic holder.
According to another suggested solution the coupling is effected through a centric threaded connection. This coupling impedes the use of automatic tool change systems, since for disconnecting the coupling a frontal access to the parts is necessary so as to quickly release the connection.
A very efficient coupling for the area of the disconnect between the machine tool and the tool system module is described in DE 38 07 140 A1. In this case, clamping or chucking elements are employed in the form of clamping claws extending across the connection portion, i.e. the disconnect, which claws--while being supported in a receiver of the machine spindle--are movable with their radially outwardly projecting claw portions into a recess of a centering extension of the part to be coupled, whereby an axial pressing force is produced. Accordingly, a homogenous distribution of force is provided across the circumference, the constructional space required by the clamping or chucking elements remaining small. However, this kind of coupling requires a drawbar centrically received in the machine spindle which comprises an actuating cone for the chuck claws at its end facing the disconnect. Therefore this coupling is suited as a coupling for components of a modular tool system only conditionally.
Attempts have already been made to employ coupling systems having a central chuck bar and wedge gear also in disconnects between a tool carrier and a stationary tool, for instance a cutter. To this effect, however, a separate and comprehensive transmission has to be provided to actuate the chuck bar extending perpendicularly to the disconnect from outside in axial direction. Apart from the fact that relatively high friction losses result from this transmission, another drawback is to be seen in that a modular series connection of plural tool components is not possible with a unitary actuation of the chuck bar.
From DE 37 15 659 A1 is known chucking means which comprises a drawbar supported to be floating truly axially in the carrier member, the drawbar extending into a coaxial recess of the part to be coupled and forming a cone portion there. The drawbar can be put under tension through this cone portion by an adjusting means supported at the part to be coupled.
This coupling distinguishes by an easy handling, a good power transmission, high concentric running accuracy and high flexibility with respect to the parts to be coupled. However, it is only conditionally compatible with a coupling as described in DE 38 07 140 A1.